1. Field of the Invention
The present invention relates to a mounting structure of an image pickup device (installed in an optical device) to which a flexible printed circuit board is mounted.
2. Description of the Related Art
Optical devices such as digital cameras and cellular phones in which a flexible printed circuit board (hereinafter referred to as a flexible PCB) to which an image pickup device is mounted are known in the art. Electrical components are also mounted to the flexible printed circuit board around the image pickup device as needed. Among such electrical components, it is desirable for transistors, resistors, capacitors, and other specific electrical components, to be arranged in the vicinity of the image pickup device for the sake of noise reduction. On the other hand, when a flexible PCB to which an image pickup device is mounted is installed in an optical device, the image pickup device is superimposed with a reinforcing plate (mounting plate) and the flexible printed circuit board. The reinforcing plate possesses high stiffness and is fastened to the back of a portion of the flexible PCB to which the image pickup device is mounted to reinforce this portion of the flexible PCB to prevent the flexible PCB, which is poor in maintaining planarity, from bending. An example of such a structure is disclosed in Japanese unexamined patent publication No. 2002-330358.
However, in the above described configuration in which a mounting board is fastened to the back of a flexible PCB, the aforementioned electrical components (transistors, resistors, capacitors, and other specific electrical components) that are desirably arranged in the vicinity of the image pickup device cannot be arranged behind the image pickup device, and accordingly, these electrical components have to be arranged on the front of the flexible PCB around the image pickup device, which becomes a cause of an increase in size of the flexible PCB.